What app you americans use for personal conversations?
Here in South Europe people mostly use Viber.
Edit: I was very unaware about situation in Southern Europe as I've learned from this post...
Most people in Croatia use Viber!
SMS. Universal and ubiquitous thanks to free or nearly free inclusion in phone plans. American English has no need for expanded character sets and carriers/Apple/Google have added just enough features on top that the vast majority of people aren't left wanting for more.
Instant payment was literally impossible until this summer, and given it's so new almost no bank has support for it yet. Privacy/encryption don't enter into most people's consciousness.